> On Jul 15, 2020, at 11:14 AM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: > > > >> On Jul 15, 2020, at 11:08 AM, Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote: >> >>> On Jul 15, 2020, at 23:02, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: >>> >>>> On Jul 15, 2020, at 10:48 AM, Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote: >>>> >>>> Hi, >>>> >>>> Multiple users reported NFS causes NULL pointer dereference [1] on Ubuntu, due to commit "SUNRPC: Add "@len" parameter to gss_unwrap()" and commit "SUNRPC: Fix GSS privacy computation of auth->au_ralign". >>>> >>>> The same issue happens on upstream stable 5.4.y branch. >>>> The mainline kernel doesn't have this issue though. >>>> >>>> Should we revert them? Or is there any missing commits need to be backported to v5.4? >>>> >>>> [1] https://bugs.launchpad.net/bugs/1886277 >>>> >>>> Kai-Heng >>> >>> 31c9590ae468 ("SUNRPC: Add "@len" parameter to gss_unwrap()") is a refactoring >>> change. It shouldn't have introduced any behavior difference. But in theory, >>> practice and theory should be the same... >>> >>> Check if 0a8e7b7d0846 ("SUNRPC: Revert 241b1f419f0e ("SUNRPC: Remove xdr_buf_trim()")") >>> is also applied to 5.4.0-40-generic. >> >> Yes, it's included. The commit is part of upstream stable 5.4. >> >>> >>> It would help to know if v5.5 stable is working for you. I haven't had any >>> problems with it. >> >> I'll ask users to test it out. >> Thanks for you quick reply! > > Another thought: Please ask what encryption type is in use. The > kerberos_v1 enctypes might exercise a code path I wasn't able to > test. OK. v5.4.40 does not have 31c9590ae468 and friends, but the claim is this one crashes? And v5.4.51 has those three and 89a3c9f5b9f0, which Pierre claims fixes the problem for him; but another commenter says v5.4.51 still crashes. So we're getting inconsistent problem reports. Have the testers enable memory debugging : KASAN or SLUB debugging might provide more information. I might have some time later this week to try reproducing on upstream stable, but no guarantees. -- Chuck Lever
